Obstructive sleep apnea (OSA) is an extremely common condition. Moderate to severe disease is associated with adverse health consequences and affects up to 17% of adult American men and 9% of adult American women. OSA is associated with an increased risk of diabetes mellitus, hypertension, congestive heart failure, and stroke. The fragmented sleep characteristic of OSA is linked to cognitive impairment, daytime sleepiness, and increased risk of motor vehicle accidents. Prevalence and severity of OSA is higher among African Americans compared with Caucasians, and African Americans are disproportionally burdened by OSA-related conditions. African Americans develop more severe disease at an earlier age and may also be more sensitive to the consequences of OSA. Continuous positive airway pressure (CPAP), which consists of a mask worn at night to deliver pressurized air, is a highly efficacious treatment for OSA. Adherence rates to this burdensome therapy can be as low as 25%. As compared to Caucasians, African Americans are five times more likely to be non-adherent to CPAP therapy. Reasons for this disparity are not completely clear. Besides symptom burden and disease severity, studies in primarily Caucasian populations have identified self-efficacy-an individual's belief in ability to achieve a goal-and socioeconomic status as predictors of CPAP adherence. Health literacy-the ability to read and utilize health information, is an important predictor of treatment adherence in other chronic diseases. Research has demonstrated that differences in health literacy explain the relationship between race and diabetes medication non-adherence among African Americans. There are no studies of health literacy among African Americans with OSA. Finally, significant differences in sleep duration by race have been noted in large cohort studies. African American sleep duration is nearly 1 hour less per night compared to Caucasians. This translates into less time available for CPAP use, and additionally short sleep duration is associated with many of the same health conditions as OSA. Sleep duration has not been objectively assessed in African Americans with OSA. Self-reported data suggests this is important, however self-report does not correlate well with objective measures and there are known differences in how sleep is reported by race. Preliminary data from our pilot study suggests that self-efficacy is positively associated with CPAP adherence in African Americans. We hypothesize that self-efficacy, sleep duration, and health literacy will explain a portion of non-adherence in African Americans as compared to Caucasians. In the proposed study, to we will recruit 50 African Americans and 50 Caucasians newly initiated on CPAP therapy. The study will take place over 90 days. Subjects will attend three visits to complete batteries of questionnaires and medical interviews. Autography, a method of monitoring activity to assess sleep patterns, will be completed for two weeks to obtain objective sleep data at time of CPAP initiation. CPAP adherence will be obtained off the CPAP machine at 30 and 90 days as our primary outcome. We will compare CPAP adherence between African Americans and Caucasians, as well as measures of self-efficacy, health literacy, and sleep duration. The proposed study will provide valuable information that will shape future work aimed at interventions to improve CPAP adherence and reduce the racial disparity in CPAP adherence. By better understanding the predictors of CPAP adherence among African Americans, appropriately targeted interventions may be developed and implemented to improve OSA-related health outcomes in this high-risk population.